#include "viewer.h"
#include "standardCamera.h"

#include <QKeyEvent>

using namespace std;
using namespace qglviewer;

Viewer::Viewer(StandardCamera *nfc) {
  // Change the camera.
  Camera *c = camera();
  setCamera(nfc);
  delete c;
}

// Draws a spiral
void Viewer::draw() {
  const float nbSteps = 200.0;

  glBegin(GL_QUAD_STRIP);
  for (int i = 0; i < nbSteps; ++i) {
    const float ratio = i / nbSteps;
    const float angle = 21.0 * ratio;
    const float c = cos(angle);
    const float s = sin(angle);
    const float r1 = 1.0 - 0.8f * ratio;
    const float r2 = 0.8f - 0.8f * ratio;
    const float alt = ratio - 0.5f;
    const float nor = 0.5f;
    const float up = sqrt(1.0 - nor * nor);
    glColor3f(1.0 - ratio, 0.2f, ratio);
    glNormal3f(nor * c, up, nor * s);
    glVertex3f(r1 * c, alt, r1 * s);
    glVertex3f(r2 * c, alt + 0.05f, r2 * s);
  }
  glEnd();
}

void Viewer::init() {
  // Restore previous viewer state.
  if (!restoreStateFromFile())
    showEntireScene();

  setKeyDescription(Qt::Key_T,
                    "Toggles camera type (perspective or orthographic)");
  setKeyDescription(Qt::Key_M, "Toggles camera mode (standard or QGLViewer)");

  setMouseBindingDescription(
      Qt::ShiftModifier, Qt::MidButton,
      "Change frustum size (for standard camera in orthographic mode)");

  // Display help window.
  help();
}

void Viewer::showMessage() {
  QString std = ((StandardCamera *)camera())->isStandard() ? "Standard camera"
                                                           : "QGLViewer camera";
  QString type =
      camera()->type() == Camera::PERSPECTIVE ? "Perspective" : "Orthographic";
  displayMessage(std + " - " + type);
  Q_EMIT cameraChanged();
}

void Viewer::keyPressEvent(QKeyEvent *e) {
  if (e->key() == Qt::Key_M) {
    // 'M' changes mode : standard or QGLViewer camera
    ((StandardCamera *)camera())->toggleMode();
    showMessage();
  } else if (e->key() == Qt::Key_T) {
    // 'T' changes the projection type : perspective or orthogonal
    if (camera()->type() == Camera::ORTHOGRAPHIC)
      camera()->setType(Camera::PERSPECTIVE);
    else
      camera()->setType(Camera::ORTHOGRAPHIC);
    showMessage();
  } else
    QGLViewer::keyPressEvent(e);
}

void Viewer::wheelEvent(QWheelEvent *e) {
  if ((camera()->type() == Camera::ORTHOGRAPHIC) &&
      (((StandardCamera *)camera())->isStandard()) &&
      (e->modifiers() & Qt::ShiftModifier)) {
    ((StandardCamera *)camera())->changeOrthoFrustumSize(e->delta());
    Q_EMIT cameraChanged();
    update();
  } else
    QGLViewer::wheelEvent(e);
}

QString Viewer::helpString() const {
  QString text("<h2>S t a n d a r d C a m e r a</h2>");
  text += "An overloaded <code>Camera</code> class is used, that reproduces "
          "the 'standard' OpenGL settings.<br><br>";

  text += "With this camera, the near and (resp. far) plane distance is set to "
          "a very small (resp. very large) value. ";
  text += "With the orthographic camera type, the frustum dimensions are "
          "fixed. Use <code>Shift</code> and the mouse wheel to change "
          "them.<br><br>";

  text += "On the other hand, the QGLViewer camera fits the near and far "
          "distances to the scene radius. ";
  text += "Fine tuning is available using <code>zClippingCoefficient()</code> "
          "and <code>zNearCoefficient()</code>. ";
  text += "However, visual results do not seem to be impacted by this zBuffer "
          "fitted range.<br><br>";
  text += "The QGLViewer camera also adapts the orthographic frustum "
          "dimensions to the distance to the <code>pivotPoint()</code> to "
          "mimic a perspective camera. ";
  text += "Since this behavior may not be needed, this example shows how to "
          "override it.<br><br>";

  text += "The second viewer displays the first one's camera to show its "
          "configuration.<br><br>";

  text += "Use <b>M</b> to switch between 'standard' and QGLViewer camera "
          "behavior.<br>";
  text += "Use <b>T</b> to switch between perspective and orthographic camera "
          "type.<br><br>";

  text += "Use <b>Shift+wheel</b> to change standard camera orthographic size.";

  return text;
}
